A method for preparing high-performance precursor nickel foam

Abstract

The present invention discloses a method for preparing a high-performance precursor nickel foam, comprising the following steps: step 1, pretreatment: (1) the nickel foam is immersed in a hydrochloric acid solution for ultrasonic treatment; (2) it is immersed in an ethanol solution and continues to be ultrasonically treated; (3) it is cleaned and dried; step 2, hydrothermal reaction: (4) triblock polymer P123, a treating agent, ethanol, water and ethylene glycol are sequentially taken, mixed and fully stirred to form a mixed solution A; (5) the nickel foam is mixed with the mixed solution A, and then subjected to a hydrothermal reaction; (6) the solid product obtained by the reaction is collected, washed and dried; step 3, heat treatment: (7) the product is placed in a tube furnace and calcined under the protection of nitrogen; (8) the product is cleaned and dried to obtain a final product. The nickel foam treated by the above technical solution has a larger specific surface area and more exposed active sites, which can effectively improve the catalytic activity of the electrocatalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a method for preparing high-performance precursor nickel foam. Background Art

[0002] In recent years, energy shortages and the need to adjust energy use have been the main themes and enduring pursuits of green chemistry, aiming at sustainable resource and environmental development. Hydrogen (H2), with its high energy density (142.4 kJ kg⁻¹) and carbon neutrality, is considered the most promising energy carrier to replace traditional fossil fuels in the future and has garnered increasing attention. Electrocatalytic water splitting is one of the most sustainable and clean hydrogen production pathways among hydrogen production technologies, and can be powered by renewable energy sources such as tidal, solar, and wind power. To improve the conversion efficiency of EWS, high-efficiency electrocatalysts are often used to reduce the overpotentials for hydrogen and oxygen evolution. Currently, the most prominent electrocatalysts are precious metal catalysts such as platinum and its derivatives, but their high price and low reserves hinder their large-scale application as high-performance electrocatalysts. Furthermore, due to the high water dissociation energy of platinum-based metals, the reaction kinetics under alkaline or neutral conditions are two to three orders of magnitude slower than under acidic conditions, further limiting the reaction rate. Therefore, developing high-performance, low-cost electrocatalysts is a significant challenge, and improving electrocatalyst performance is a key issue for the large-scale application of fuel cells.

[0003] Nickel foam (NF) has a unique open-pore structure, low-pressure injection holes, inherent tensile strength, and thermal shock resistance, making it a promising catalyst support for fuel cell catalytic converters and catalytic combustion. During cold engine starts, carbon monoxide and hydrocarbons are converted. Due to its thermal conductivity, nickel foam catalyst supports may be superior to ceramic catalyst supports. In this sense, nickel foam can be comparable to or even superior to high-temperature resistant steel catalyst supports. Before further use as a catalyst support, it is usually pretreated to remove surface oxides and oils. For example, NF can be treated with acetone, ethanol, deionized water, and other processes to enhance its catalytic activity.

[0004] Currently, most pretreatment methods in this field typically use a certain concentration of hydrochloric acid (HCl) and ultrasound to remove surface oxides. This is followed by ultrasound removal of surface oil contamination using organic solvents such as ethanol and acetone. The disadvantage of this technique is that it only cleans the nickel foam without improving its intrinsic activity, and its electrochemical performance remains essentially unchanged.

[0005] Therefore, it is necessary to provide a treatment method that can better exert the performance of the catalyst. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a high-performance precursor nickel foam to solve one or more technical problems existing in the prior art and at least provide a beneficial option or create conditions.

[0007] The purpose of the present invention is achieved by adopting the following technical solutions:

[0008] A method for preparing a high-performance precursor nickel foam comprises the following steps:

[0009] Step 1, pre-processing:

[0010] (1) Soaking nickel foam in hydrochloric acid solution and ultrasonic treatment;

[0011] (2) Take out and clean it, then soak it in ethanol solution and continue ultrasonic treatment;

[0012] (3) Take out and clean, dry and set aside;

[0013] Step 2, hydrothermal reaction:

[0014] (4) taking triblock polymer P123, treating agent, ethanol, water and ethylene glycol in sequence, mixing and stirring thoroughly to form a mixed solution A;

[0015] (5) mixing the pre-treated nickel foam with the mixed solution A, placing the mixture in a hydrothermal reactor, and then performing a hydrothermal reaction;

[0016] (6) After the reaction is completed, the solid product obtained by the reaction is collected, washed, and dried;

[0017] Step 3, heat treatment:

[0018] (7) placing the product after the hydrothermal reaction in a tubular furnace and calcining it under the protection of nitrogen;

[0019] (8) The calcined product is washed and dried to obtain the final product.

[0020] Preferably, in the pretreatment step, the concentration of hydrochloric acid is 3 mol / L, the size of the nickel foam is 2 cm in length and 3 cm in width, and the ultrasonic time in the hydrochloric acid solution is 15 min.

[0021] Preferably, in the pre-treatment step, the cleaning is performed by rinsing three times with deionized water.

[0022] Preferably, in the pretreatment step, the amount of ethanol solution used is 50 mL, and the ultrasonic time in the ethanol solution is 15 min.

[0023] Preferably, in the pre-treatment step, drying is performed by placing the product in a vacuum drying oven.

[0024] Preferably, in the hydrothermal reaction step, the amount of triblock polymer P123 added is 0.8 g, the amount of ethanol added is 12 g, the amount of water added is 4 g, and the amount of ethylene glycol added is 30 mL.

[0025] Preferably, in the hydrothermal reaction step, the treating agent includes any one of ethylenediaminetetraacetic acid (EDTA), thiourea, urea, methylamine, hydrogenated partial anhydride (HMTA), and ammonia water.

[0026] More preferably, in the hydrothermal reaction step, the treating agent is ethylenediaminetetraacetic acid (EDTA), and the added amount is 1.24 g.

[0027] The treatment agent chosen is ethylenediaminetetraacetic acid (EDTA). EDTA reacts with the divalent nickel ions in the nickel foam during the hydrothermal reaction and forms a stable complex with them, making the solution appear blue. This process causes the surface of the nickel foam to partially dissolve, and then it will be deposited back on the surface of the nickel foam during the cooling process after the reaction, forming active sites that are conducive to electrochemical reactions.

[0028] Preferably, in the hydrothermal reaction step, the hydrothermal reaction temperature is 120° C. and the reaction time is 12 h.

[0029] Preferably, in the hydrothermal reaction step, after the hydrothermal reaction, the product is washed with deionized water for more than three times; and dried by placing the product in a vacuum drying oven at 60° C. for more than 6 hours.

[0030] Preferably, in the heat treatment step, the temperature of the tube furnace is 300° C., the calcination time is 5 min, and the heating rate is 5° C. / min.

[0031] Preferably, in the heat treatment step, the cleaning is performed by repeatedly rinsing with deionized water for more than three times, and the drying is performed by placing the product in a vacuum drying oven for more than 6 hours.

[0032] The beneficial effects of the present invention are:

[0033] The nickel foam treated using the above-described technical solution has a larger specific surface area and more exposed active sites, which can effectively enhance the catalytic activity of the electrocatalyst. Compared to the existing technology that simply cleans the nickel foam, the dissolution and re-deposition process of the present invention can give the nickel foam a larger electrochemically active surface area and more active sites that are conducive to electrochemical reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is further described with reference to the accompanying drawings. However, the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative effort.

[0035] Figure 1 This is a performance comparison chart of the products prepared in Examples 1-7 of the present invention;

[0036] Figure 2 This is a scanning electron micrograph (100 μm) of NF-EDTA prepared and synthesized in Example 7 of the present invention;

[0037] Figure 3 1 is a scanning electron micrograph (500 nm) of NF-EDTA prepared and synthesized in Example 7 of the present invention. DETAILED DESCRIPTION

[0038] In order to more clearly illustrate the present invention and have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0039] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0040] The present invention is further described with reference to the following examples.

[0041] Example 1

[0042] A method for preparing a high-performance precursor nickel foam comprises the following steps:

[0043] Step 1, pre-processing:

[0044] (1) Soaking nickel foam in hydrochloric acid solution and ultrasonic treatment;

[0045] (2) Take out and clean it, then soak it in ethanol solution and continue ultrasonic treatment;

[0046] (3) Take out and clean, dry and set aside;

[0047] Step 2, hydrothermal reaction:

[0048] (4) taking triblock polymer P123, treating agent, ethanol, water and ethylene glycol in sequence, mixing and stirring thoroughly to form a mixed solution A;

[0049] (5) mixing the pre-treated nickel foam with the mixed solution A, placing the mixture in a hydrothermal reactor, and then performing a hydrothermal reaction;

[0050] (6) After the reaction is completed, the solid product obtained by the reaction is collected, washed, and dried;

[0051] Step 3, heat treatment:

[0052] (7) placing the product after the hydrothermal reaction in a tubular furnace and calcining it under the protection of nitrogen;

[0053] (8) The calcined product is washed and dried to obtain the final product.

[0054] Specifically, this embodiment includes the following steps:

[0055] 1. Cleaning

[0056] (1) Prepare 3 mol / L HCl and place it in a 2*3 cm nickel foam, and ultrasonically clean it for 15 min;

[0057] (2) Take out the nickel foam from step 1, rinse it three times with deionized water, add 50 ml of ethanol solution, and ultrasonically clean it for 15 minutes;

[0058] (3) Take out the nickel foam in step 2, rinse it three times with deionized water, and put it into a vacuum drying oven for later use;

[0059] 2. Hydrothermal

[0060] (4) Add 0.8 g P123, 0.3 g thiourea, 12 g ethanol, 4 g water, and 30 ml ethylene glycol and stir for 30 minutes to fully dissolve;

[0061] (5) The nickel foam in step 3 and the solution in step 4 were placed in a 100 ml hydrothermal reactor and placed in a forced air drying oven at 120° C. for 12 hours.

[0062] (6) Take out the nickel foam in step 5, rinse it repeatedly with deionized water for more than three times, and place it in a vacuum drying oven at 60° C. for more than 6 hours.

[0063] 3. Heat treatment

[0064] (7) Take out the nickel foam in step 6, put it into a tubular furnace and calcine it in nitrogen at a temperature of 300°C for 5 minutes, with a heating rate of 5°C / min. The purpose of this operation is to remove the volatile organic matter on the surface of the nickel foam and to fix the microstructure after the hydrothermal reaction and the alkali action. At the same time, calcination can increase the crystallinity of the nanosheets on the nickel foam and improve the conductive properties of the nickel foam.

[0065] (8) Take out the nickel foam from step 7, rinse it repeatedly with deionized water for more than three times, place it in a vacuum drying oven for more than 6 hours to dry, and mark it as NF-Thiourea.

[0066] Example 2

[0067] The preparation method of the high-performance precursor nickel foam provided in this embodiment, the raw material components for preparing the electrocatalyst and its preparation method are basically the same as those in Example 1, except that in Example 2, thiourea (Thiourea) is replaced by urea (Urea) in an amount of 0.26 g. The prepared electrocatalyst sample is marked as NF-Urea.

[0068] Example 3

[0069] The preparation method of the high-performance precursor nickel foam provided in this embodiment, the raw material components for preparing the electrocatalyst and its preparation method are basically the same as those in Example 1, the difference being that thiourea is removed in Example 3, and the obtained electrocatalyst sample is marked as NF.

[0070] Example 4

[0071] The preparation method of the high-performance precursor nickel foam provided in this embodiment, the raw material components for preparing the electrocatalyst and its preparation method are basically the same as those in Example 1, except that in Example 4, thiourea is replaced by methylamine (Methylamine) in an amount of 0.65 g. The prepared electrocatalyst sample is marked as NF-Mehylamine.

[0072] Example 5

[0073] The preparation method of the high-performance precursor nickel foam provided in this embodiment, the raw material components for preparing the electrocatalyst and its preparation method are basically the same as those in Example 1, except that in Example 5, thiourea is replaced by hexamethylenetetramine (HMTA) in an amount of 0.3 g. The prepared electrocatalyst sample is marked as NF-HMTA.

[0074] Example 6

[0075] The preparation method of the high-performance precursor nickel foam provided in this embodiment, the raw material components for preparing the electrocatalyst and its preparation method are basically the same as those in Example 1, except that in Example 6, thiourea is replaced with ammonia water in an amount of 0.48 g. The prepared electrocatalyst sample is marked as NF-NH4.

[0076] Example 7

[0077] The preparation method of the high-performance precursor nickel foam provided in this embodiment, the raw material components for preparing the electrocatalyst and its preparation method are basically the same as those in Example 1, except that in Example 6, thiourea is replaced by EDTA in an amount of 1.24 g. The prepared electrocatalyst sample is marked as NF-EDTA.

[0078] The present invention Figure 1Because the picture in the briefing book is in black and white, a one-to-one correspondence was made between the legend on the left and the lines on the right when drawing. That is, the left-side logo from top to bottom corresponds to the right-side lines from top to bottom (judged at the horizontal coordinate -0.2). The top line on the right is NF-Thiourea and the bottom one is NF-EDTA.

[0079] Table 1 Performance comparison of products prepared in different embodiments

[0080] sample Corresponding embodiment <![CDATA[10mA·cm -2 Overpotential (mV)]]> impedance NF-Thiourea Example 1 376 237 NF-Urea Example 2 345 95 NF Example 3 327 78 NF-Methylamine Example 4 341 91 NF-HMTA Example 5 309 51 <![CDATA[NF-NH4]]> Example 6 306 53 NF-EDTA Example 7 285 45

[0081] From the analysis in Table 1, when comparing the electrochemical performance, the product is usually compared at 10 mA cm -2 The overpotential and the impedance of the product are related to the product. The smaller the overpotential and the smaller the impedance, the better the electrochemical performance of the product. Therefore, the present invention emphasizes that the NF-EDTA sample group after the operation and treatment of the present invention has the best performance.

[0082] In the above-mentioned embodiment of the present invention, the nickel foam treated by the new technical solution has a larger specific surface area and more exposed active sites, which can effectively improve the catalytic activity of the electrocatalyst.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a high-performance precursor nickel foam, characterized in that: The following steps are involved: Step 1, pre-processing: (1) Soak the nickel foam in a hydrochloric acid solution and perform ultrasonic treatment; (2) Take out and clean it, then soak it in ethanol solution and continue ultrasonic treatment; (3) Take out and clean, dry and set aside; Step 2, hydrothermal reaction: (4) Triblock polymer P123, treatment agent, ethanol, water, and ethylene glycol were sequentially mixed and stirred to form a mixed solution A; (5) Mixing the pre-treated nickel foam with the mixed solution A, placing the mixture in a hydrothermal reactor, and then performing a hydrothermal reaction; (6) After the reaction is completed, the solid product obtained is collected, washed, and dried; Step 3, heat treatment: (7) placing the product after the hydrothermal reaction in a tubular furnace and calcining it under the protection of nitrogen; (8) The calcined product is washed and dried to obtain the final product; In the hydrothermal reaction step, the amount of triblock polymer P123 added is 0.8 g, the amount of ethanol added is 12 g, the amount of water added is 4 g, and the amount of ethylene glycol added is 30 mL; In the hydrothermal reaction step, the treating agent is ethylenediaminetetraacetic acid (EDTA), and the added amount is 1.24 g; In the heat treatment step, the temperature of the tube furnace is 300° C., the calcination time is 5 min, and the heating rate is 5° C. / min.

2. The method for preparing a high-performance precursor nickel foam according to claim 1, wherein: In the pretreatment step, the concentration of hydrochloric acid is 3 mol / L, the size of the nickel foam is 2 cm in length and 3 cm in width, and the ultrasonic time in the hydrochloric acid solution is 15 minutes.

3. The method for preparing a high-performance precursor nickel foam according to claim 1, wherein: In the pre-treatment steps, the cleaning step is to rinse three times with deionized water, and the drying step is to dry in a vacuum drying oven.

4. The method for preparing a high-performance precursor nickel foam according to claim 1, wherein: In the pretreatment step, the amount of ethanol solution used is 50 mL, and the ultrasonic time in the ethanol solution is 15 min.

5. The method for preparing a high-performance precursor nickel foam according to claim 1, wherein: In the hydrothermal reaction step, the hydrothermal reaction temperature is 120° C. and the reaction time is 12 h.

6. The method for preparing a high-performance precursor nickel foam according to claim 1, wherein: In the hydrothermal reaction step, after the hydrothermal reaction, the product is washed with deionized water for more than three times; and dried by placing the product in a vacuum drying oven at 60° C. for more than 6 hours.

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